Explanation of Several Different Scale Models of Platinum Rhodium Thermocouples

Platinum and rhodium thermocouples are also known as high-temperature precious metal thermocouples. They are divided into three types: S-type thermocouples (platinum and rhodium 10 platinum thermocouples), R-type thermocouples (platinum and rhodium 13 platinum thermocouples), and B-type thermocouples (platinum and rhodium 30 platinum and rhodium 6 thermocouples). They are mainly divided into single platinum rhodium and double platinum rhodium. They are suitable for various high-temperature applications. S-type thermocouple is a commonly used type of platinum rhodium thermocouple in domestic industry. Due to the high measurement temperature, ordinary stainless steel protective tubes can only withstand temperatures up to 1000 degrees Celsius. Stainless steel protective tubes that can withstand temperatures above 1000 degrees Celsius are expensive, so commonly used corundum ceramic protective tubes. High purity corundum tubes can withstand temperatures up to 1600 degrees Celsius or even higher. Although they can withstand high temperatures, they also have their disadvantages. Ceramics are easily damaged by external force collisions. Therefore, when packaging, we will customize wooden boxes with hanging baskets for transportation.

S-type thermocouple (platinum rhodium 10 platinum thermocouple):

Platinum rhodium 10 platinum thermocouple (S-type thermocouple) is a precious metal thermocouple. The diameter of the coupling wire is specified as 0.5 millimeters, with an allowable deviation of -0.015 millimeters. The nominal chemical composition of its positive electrode (sp) is platinum rhodium alloy, containing 10% rhodium and 90% platinum, and the negative electrode (SN) is pure platinum. Therefore, it is generally called a single platinum rhodium thermocouple. The long-term high working temperature of the thermocouple is 1300 ℃, and the short-term high working temperature is 1600 ℃.

R-type thermocouple (platinum rhodium 13 platinum thermocouple):

Platinum rhodium 13 platinum thermocouple (R-type thermocouple) is a precious metal thermocouple. The diameter of the coupling wire is specified as 0.5 millimeters, with an allowable deviation of -0.015 millimeters. The nominal chemical composition of its positive electrode (RP) is platinum rhodium alloy, including 13% rhodium and 87% platinum. The negative electrode (RN) is pure platinum, with a high long-term use temperature of 1300 ℃ and a high short-term use temperature of 1600 ℃.

B-type thermocouple (platinum rhodium 30 platinum rhodium 6 thermocouple):

Platinum rhodium 30 platinum rhodium 6 thermocouple (type B thermocouple) is a precious metal thermocouple. The diameter of the coupling line is specified as 0.5 millimeters, with an allowable deviation of -0.015 millimeters. The nominal chemical composition of its positive electrode is platinum rhodium alloy, including 30% rhodium and 70% platinum, and the negative electrode is platinum rhodium alloy with a rhodium content of 6%, so it is commonly referred to as a dual platinum rhodium thermocouple. The long-term high working temperature of thermocouples is 1600 ℃, and the short-term high working temperature is 1800 ℃.